Polymers derived from benzobis(silolothiophene) and their use as organic semiconductors

ABSTRACT

The invention relates to conjugated polymers comprising benzo-bis(silolothiophene) units or derivatives thereof, to methods of their preparation, to novel monomer units used therein, to the use of the polymers in organic electronic (OE) devices, and to OE devices comprising the polymers.

FIELD OF THE INVENTION

The invention relates to conjugated polymers comprisingbenzo-bis(silolothiophene) units or derivatives thereof, to methods oftheir preparation, to novel monomer units used therein, to the use ofthe polymers in organic electronic (OE) devices, and to OE devicescomprising the polymers.

BACKGROUND AND PRIOR ART

In recent years, there has been development of organic semiconducting(OSC) materials in order to produce more versatile, lower costelectronic devices. Such materials find application in a wide range ofdevices or apparatus, including organic field effect transistors(OFETs), organic light emitting diodes (OLEDs), photodetectors, organicphotovoltaic (OPV) cells, sensors, memory elements and logic circuits toname just a few. The organic semiconducting materials are typicallypresent in the electronic device in the form of a thin layer, forexample less than 1 micron thick.

The performance of OFET devices is principally based upon the chargecarrier mobility of the semiconducting material and the current on/offratio, so the ideal semiconductor should have a low conductivity in theoff state, combined with a high charge carrier mobility (>1×10⁻³ cm² V⁻¹s⁻¹). In addition, it is important that the semiconducting material isrelatively stable to oxidation i.e. it has a high ionisation potential,as oxidation leads to reduced device performance. Further requirementsfor the semiconducting material are a good processability, especiallyfor large-scale production of thin layers and desired patterns, and highstability, film uniformity and integrity of the organic semiconductorlayer.

In prior art various materials have been proposed for use as OSCs inOFETs, including small molecules like for example pentacene, andpolymers like for example polyhexylthiophene. However, the materials anddevices investigated so far do still have several drawbacks, and theirproperties, especially the processability, charge-carrier mobility,on/off ratio and stability do still leave room for further improvement.

Generally there is a need for OSC materials that show high chargecarrier mobility. Moreover, for use in OFETs there is a need for OSCmaterials that allow improved charge injection into the polymersemiconducting layer from the source-drain electrodes. For use in OPVcells, there is a need for OSC materials having a low bandgap, whichenable improved light harvesting by the photoactive layer and can leadto higher cell efficiencies.

For use in OPV devices, especially for bulk heterojunction (BHJ) OPVdevices, there is a strong need for novel p-type organic semiconductormaterials that give improved device performance and do not have thedrawbacks of the materials of prior art. The limitations of existingp-type materials relate to deficiencies in light absorption, oxidativestability and charge-carrier mobility. In particular, the new materialsshould demonstrate the following properties:

-   -   low bandgap,    -   high charge carrier mobility,    -   being easy to synthesize,    -   high solubility in organic solvents,    -   good processability for the device manufacture process,    -   high oxidative stability    -   long lifetime in electronic devices.

One aim of the present invention is to provide new p-type OSC materials,especially for use in BHJ OPV devices, fulfilling the above-mentionedrequirements. Another aim is to extend the pool of OSC materialsavailable to the expert. Other aims of the present invention areimmediately evident to the expert from the following detaileddescription.

The inventors of the present invention have found that these aims can beachieved by providing OSC materials as described hereinafter. These OSCmaterials are based on polymers comprising one or more benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b]thiophene) units or thecorresponding selenophene derivatives thereof, as represented by thefollowing formulae:

(wherein X is S or Se and R¹⁻⁴ denote for example hydrocarbyl groups)

In prior art the approach to provide low bandgap polymers suitable forapplication in BHJ photovoltaic devices often is achieved by an increasein the HOMO energy level. The negative implications of this are apotentially higher susceptibility of the polymer to oxidative doping anda loss in the prospective open-circuit voltage (V_(oc)) in a BHJ device,which reduces device efficiency.

In contrast thereto, by using the new polymers as described hereinafterthe inventors of the present invention follow an approach that lowersthe LUMO energy level in the polymer without affecting the HOMO energylevel. Thereby a low bandgap polymer can be obtained without thedisadvantages mentioned above. In particular the inclusion of siliconbridging atoms into conjugated species lowers the LUMO energy level.

The polymers of this invention are therefore suitable for use as p-typeOSC materials in electronic devices like OFETs and OPV cells, especiallyin BHJ OPV devices.

SUMMARY OF THE INVENTION

The invention relates to conjugated polymers comprising one or moreidentical or different repeating units of formula I

wherein

one of A¹ and A² is a single bond and the other is SiR¹R²,

one of A³ and A⁴ is a single bond and the other is SiR³R⁴,

one of U¹ and U² is —CH═ or ═CH— and the other is —X—,

one of U³ and U⁴ is —CH═ or ═CH— and the other is —X—,

-   -   X is in each occurrence independently selected from —S— and        —Se—,    -   R¹⁻⁴ are identical or different groups independently of each        other selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN,        —SCN, —C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH,        —SR⁰, —SO₃H, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF_(S), P-Sp-, optionally        substituted silyl, or carbyl or hydrocarbyl with 1 to 40 C atoms        that is optionally substituted and optionally comprises one or        more hetero atoms,

P is a polymerisable group,

Sp is a spacer group or a single bond,

X⁰ is halogen,

R⁰ and R⁰⁰ are independently of each other H or an optionallysubstituted carbyl or hydrocarbyl group optionally comprising one ormore hetero atoms,

Ar¹ and Ar² are independently of each other an optionally substitutedaryl or heterorayl group, —CY¹═CY²— or —C≡C—,

Y¹ and Y² are independently of each other H, F, Cl or CN,

m1 and m2 are independently of each other 0 or 1, 2, 3 or 4.

The invention further relates to a formulation comprising one or morepolymers or polymer blends according to the present invention and one ormore solvents, preferably selected from organic solvents.

The invention further relates to a polymer blend comprising one or morepolymers according to the present invention and one or more polymers,preferably selected from polymers having semiconducting, chargetransport, hole/electron transport, hole/electron blocking, electricallyconducting, photoconducting or light emitting properties.

The invention further relates to the use of polymers, polymer blends andformulations according to the present invention as charge transport,semiconducting, electrically conducting, photoconducting or lightemitting material in optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices.

The invention further relates to a charge transport, semiconducting,electrically conducting, photoconducting or light emitting material orcomponent comprising one or more polymers, polymer blends offormulations according to the present invention.

The invention further relates to an optical, electrooptical orelectronic component or device comprising one or more polymers, polymerblends, formulations, components or materials according to the presentinvention.

The optical, electrooptical, electronic electroluminescent andphotoluminescent components or devices include, without limitation,organic field effect transistors (OFET), thin film transistors (TFT),integrated circuits (IC), logic circuits, capacitors, radio frequencyidentification (RFID) tags, devices or components, organic lightemitting diodes (OLED), organic light emitting transistors (OLET), flatpanel displays, backlights of displays, organic photovoltaic devices(OPV), solar cells, laser diodes, photoconductors, photodetectors,electrophotographic devices, electrophotographic recording devices,organic memory devices, sensor devices, charge injection layers, chargetransport layers or interlayers in polymer light emitting diodes(PLEDs), Schottky diodes, planarising layers, antistatic films, polymerelectrolyte membranes (PEM), conducting substrates, conducting patterns,electrode materials in batteries, alignment layers, biosensors,biochips, security markings, security devices, and components or devicesfor detecting and discriminating DNA sequences.

Especially preferred components and devices are bulk heterojunction OPVdevices.

DETAILED DESCRIPTION OF THE INVENTION

The polymers according to the present invention are easy to synthesizeand exhibit several advantageous properties, like a low bandgap, a highcharge carrier mobility, a high solubility in organic solvents, a goodprocessability for the device manufacture process, a high oxidativestability and a long lifetime in electronic devices. In addition, theyshow the following advantageous properties:

-   -   i) The        benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b]thiophene)        unit exhibits a co-planar structure in the solid state, and        consequently individual polymer chains of the homopolymer,        poly[benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b′]thiophene)],        do also adopt a highly co-planar structure in the solid-state,        which is beneficial for charge transport. A structurally similar        silole structure, namely a        benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b′]benzo-thiophene)        derivative, has been reported to exhibit a co-planar structure        according to X-ray crystallographic analysis [see K. Mouri, A.        Wakamiya, H. Yamada, T. Kajiwara and S. Yamaguchi, Org. Lett.,        2007, 9, 93].    -   ii) The inclusion of two silicon bridging atoms in the        benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b′]thiophene)        unit results in polymers with a lower lying LUMO energy level        that yields a low bandgap, which is desirable for improved light        harvesting and higher efficiencies in BHJ devices without any        change in the HOMO energy level or V_(oc), loss in the device.    -   iii) Additional fine-tuning of the HOMO energy level by either        further modification of the        benzo[1″,2″:4,5;4″,5″:4′,5′]bis(silolo[3,2-b:3′,2′-b′]thiophene)        core or co-polymerisation with appropriate electron-donating or        electron-deficient co-monomer(s) allows further modification of        the bandgap. This affords low bandgap polymers that are        advantageous in BHJ photovoltaic cells due to improved light        harvesting, and gives way to higher BHJ cell efficiencies.    -   iv) Additional solubility can be introduced into the polymer by        adding at the silyl group longer alkyl chains, branched alkyl        chains or polyalkoxy ethers or co-monomers containing multiple        solubilising groups.

The conjugated polymers are preferably selected of formula la

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1 and m2 have the meanings of formula Iand n is an integer >1.

Especially preferred are polymers of formula Ib

wherein U¹⁻⁴, A¹⁻⁴, Ar¹⁻², m1, m2 and n have the meanings of formula Ia,and

-   -   R⁵ and R⁶ have independently of each other one of the meanings        of R¹ or denote H, halogen, —CH₂Cl, —CHO, —CH═CH₂—SiR′R″R′″,        —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂, or P-Sp, wherein P        and Sp are as defined above, and R′, R″ and R′″ have        independently of each other one of the meanings of R⁰ given        above and R′ and R″ may also form a ring together with the        hetero atom to which the are attached.

Especially preferred are polymers comprising one or more identical ordifferent repeating units selected from the group consisting of thefollowing subformulae:

wherein R¹⁻⁴ are as defined in formula I and Ar has one of the meaningsof Ar¹ given above and below.

Especially preferred are repeating units of formulae I1-I16.

The polymers of the present invention preferably comprise, verypreferably consist of, one or more identical or different monomericunits selected from the group consisting of subformulae I1-I32.

Further preferred are polymers of formula Ia1:-(MU)_(n)-  Ia1

wherein n is as defined in formula Ia and “MU” is a monomeric repeatingunit selected from the group consisting of subformulae I1-I32, mostpreferably from the group consisting of subformulae I1-I16.

Further preferred are polymers of formula Ib1:R⁵-(MU)_(n)-R⁶  Ib1

wherein R⁵, R⁶ and n are as defined in formula Ib, and “MU” is amonomeric repeating unit selected from the group consisting ofsubformulae I1-I32, most preferably from the group consisting ofsubformulae I1-I16.

Further preferred are polymers of the above-mentioned formulae whereinAr is, 1,3-benzothiadiazole-4,7-diyl or2,1,3-benzoselenadiazole-4,7-diyl.

Especially preferred are polymers of the following formula:

wherein n is as defined in formula Ia, R has one of the meanings of R¹as given above, and is preferably selected from the group consisting ofC₁-C₂₀-alkyl, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl,C₁-C₂₀-thioalkyl, C₁-C₂₀-silyl, C₁-C₂₀-ester, C₁-C₂₀-amino, andC₁-C₂₀-fluoroalkyl, all of which are straight-chain or branched.

Another aspect of the invention relates to monomers of formula II

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1 and m2 have the meanings of formula I,and

-   -   R⁷ and R⁸ denote independently of each other halogen, —CH₂Cl,        —CHO, —CH═CH₂, —SiR′R″R′″, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″),        —B(OH)₂, a leaving group or P-Sp, wherein P and Sp are as        defined above, and R′, R″ and R′″ have independently of each        other one of the meanings of R⁰ given above or denote halogen,        and R′ and R″ may also form a ring together with the hetero atom        to which they are attached.

Especially preferred are monomers selected of formula II1:R⁷-MU-R⁸  II1

wherein R⁷ and R⁸ are as defined in formula II, and “MU” is a monomericunit selected from the group consisting of subformulae I1-I32, mostpreferably from the group consisting of subformulae I1-I16.

Especially preferred are units of formula I, polymers of formula Ia andIb, and monomers of formula II, and their preferred subformulae as shownabove and below, wherein

-   -   if A¹ is a single bond U¹ is X and/or if A² is a single bond U²        is X and/or if A³ is a single bond U³ is X and/or if A⁴ is a        single bond U⁴ is X,    -   X is S,    -   R¹⁻⁴ are independently of each other selected from, preferably        straight-chain or branched, C₁-C₂₀-alkyl, C₁-C₂₀-alkoxy,        C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₁-C₂₀-thioalkyl, C₁-C₂₀-silyl,        C₁-C₂₀-ester, C₁-C₂₀-amino, and C₁-C₂₀-fluoroalkyl,    -   R¹⁻⁴ are H,    -   m1 and m2 are 0,    -   m1 and m2 are 1 or 2,    -   m2 is 0 and m1 is 1 or 2,    -   Ar¹ and Ar² are independently of each other aryl or heteroaryl,        preferably selected from the group consisting of        2,1,3-benzothiadiazole-4,7-diyl,        2,1,3-benzoselenadiazole-4,7-diyl,        4,7-bis(2-thienyl)-2,1,3-benzothiadiazole-5,5′-diyl,        4,7-bis(2-selenophenyl)-2,1,3-benzothiadiazole-5,5′-diyl,        2,3-dicyano-1,4-phenylene, 2,5-dicyano, 1,4-phenylene,        2,3-difluro-1,4-phenylene, 2,5-difluoro, 1,4-phenylene,        2,3,5,6-tetrafluoro, 1,4-phenylene,        3,4-difluorothiophene-2,5-diyl, thieno[3,4-b]pyrazine-2,5-diyl,        quinoxaline-5,8-diyl, selenophene-2,5-diyl, thiophene-2,5-diyl,        thieno[3,2-b]thiophene-2,5-diyl,        thieno[2,3-b]thiophene-2,5-diyl,        selenopheno[3,2-b]selenophene-2,5-diyl,        selenopheno[2,3-b]selenophene-2,5-diyl,        selenopheno[3,2-b]thiophene-2,5-diyl,        selenopheno[2,3-b]thiophene-2,5-diyl, 1,4-phenylene,        pyridine-2,5-diyl, pyrimidine-2,5-diyl, p-p′-biphenyl,        naphthalene-2,6-diyl, benzo[1,2-b:4,5-b]dithiophene-2,6-diyl,        2,2-dithiophene, 2,2-diselenophene, thiazole and oxazole, all of        which are unsubstituted, mono- or polysubstituted, preferably        with R′ as defined above, especially preferably with m being 1        or 2,    -   n is at least 4, preferably at least 10, very preferably at        least 50, and up to 5000, preferably up to 1000.    -   Mw is at least 5,000, preferably at least 10,000, very        preferably at least 20,000, and is up to 300,000 preferably up        to 200,000,    -   R⁵ and R⁶ are selected from H, halogen, —CH₂Cl, —CHO,        —CH═CH₂—SiR′R″R′″, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂,        P-Sp, C₁-C₂₀-alkyl, C₁-C₂₀-alkoxy, C₂-C₂₀-alkenyl,        C₁-C₂₀-fluoroalkyl and optionally substituted aryl or        heteroaryl,    -   R⁷ and R⁸ are, preferably independently of each other, selected        from the group consisting of Cl, Br, I, O-tosylate, O-triflate,        O-mesylate, O-nonaflate, —SiMe₂F, —SiMeF₂, —O—SO₂Z, —B(OZ¹)₂,        —CZ²═C(Z²)₂, —C≡CH and —Sn(Z³)₃, wherein Z and Z¹⁻³ are selected        from the group consisting of alkyl and aryl, each being        optionally substituted, and two groups Z¹ may also form a cyclic        group,    -   at least one, preferably one or two of R¹⁻⁴ denote P-Sp-,

The polymers of the present invention include homopolymers andcopolymers, like statistical or random copolymers, alternatingcopolymers and block copolymers, as well as combinations thereof.

In the polymers according to the present invention, the total number ofrepeating units n is preferably 4, very preferably 10, most preferably50, and preferably up to 1000, very preferably up to 2,000, mostpreferably up to 5,000, including any combination of the aforementionedlower and upper limits of n.

The term “polymer” generally means a molecule of high relative molecularmass, the structure of which essentially comprises the multiplerepetition of units derived, actually or conceptually, from molecules oflow relative molecular mass (PAC, 1996, 68, 2291). The term “oligomer”generally means a molecule of intermediate relative molecular mass, thestructure of which essentially comprises a small plurality of unitsderived, actually or conceptually, from molecules of lower relativemolecular mass (PAC, 1996, 68, 2291). In a preferred sense according tothe present invention a polymer means a compound having >1, preferably 5repeating units, and an oligomer means a compound with >1 and <10,preferably <5, repeating units.

The term “repeating unit” means the constitutional repeating unit (CRU),which is the smallest constitutional unit the repetition of whichconstitutes a regular macromolecule, a regular oligomer molecule, aregular block or a regular chain (PAC, 1996, 68, 2291).

The term “leaving group” means an atom or group (charged or uncharged)that becomes detached from an atom in what is considered to be theresidual or main part of the molecule taking part in a specifiedreaction (see also PAC, 1994, 66, 1134).

The term “conjugated” means a compound containing mainly C atoms withsp²-hybridisation (or optionally also sp-hybridisation), which may alsobe replaced by hetero atoms. In the simplest case this is for example acompound with alternating C—C single and double (or triple) bonds, butdoes also include compounds with units like 1,3-phenylene. “Mainly”means in this connection that a compound with naturally (spontaneously)occurring defects, which may lead to interruption of the conjugation, isstill regarded as a conjugated compound.

Unless stated otherwise, the molecular weight is given as the numberaverage molecular weight M_(n) or weight average molecular weight M_(W),which is determined by gel permeation chromatography (GPC) againstpolystyrene standards. The degree of polymerization (n) means the numberaverage degree of polymerization, given as n=M_(n)/M_(U), wherein M_(U)is the molecular weight of the single repeating unit.

The term “carbyl group” as used above and below denotes any monovalentor multivalent organic radical moiety which comprises at least onecarbon atom either without any non-carbon atoms (like for example—C≡C—), or optionally combined with at least one non-carbon atom such asN, O, S, P, Si, Se, As, Te or Ge (for example carbonyl etc.). The term“hydrocarbyl group” denotes a carbyl group that does additionallycontain one or more H atoms and optionally contains one or more heteroatoms like for example N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group comprising a chain of 3 or more C atomsmay also be linear, branched and/or cyclic, including spiro and/or fusedrings.

Preferred carbyl and hydrocarbyl groups include alkyl, alkoxy,alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy,each of which is optionally substituted and has 1 to 40, preferably 1 to25, very preferably 1 to 18 C atoms, furthermore optionally substitutedaryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, furthermorealkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy andaryloxycarbonyloxy, each of which is optionally substituted and has 6 to40, preferably 7 to 40 C atoms.

The carbyl or hydrocarbyl group may be a saturated or unsaturatedacyclic group, or a saturated or unsaturated cyclic group. Unsaturatedacyclic or cyclic groups are preferred, especially aryl, alkenyl andalkynyl groups (especially ethynyl). Where the C₁-C₄₀ carbyl orhydrocarbyl group is acyclic, the group may be linear or branched. TheC₁-C₄₀ carbyl or hydrocarbyl group includes for example: a C₁-C₄₀ alkylgroup, a C₂-C₄₀ alkenyl group, a C₂-C₄₀ alkynyl group, a C₃-C₄₀ allylgroup, a C₄-C₄₀ alkyldienyl group, a C₄-C₄₀ polyenyl group, a C₆-C₁₈aryl group, a C₂-C₁₈ heteroaryl group, a C₆-C₄₀ alkylaryl group, aC₆-C₄₀ arylalkyl group, a C₄-C₄₀ cycloalkyl group, a C₄-C₄₀ cycloalkenylgroup, and the like. Preferred among the foregoing groups are a C₁-C₂₀alkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₃-C₂₀allyl group, a C₄-C₂₀ alkyldienyl group, a C₆-C₁₂ aryl group, a C₂-C₁₂heteroaryl group and a C₄-C₂₀ polyenyl group, respectively. Alsoincluded are combinations of groups having carbon atoms and groupshaving hetero atoms, like e.g. an alkynyl group, preferably ethynyl,that is substituted with a silyl group, preferably a trialkylsilylgroup.

Further preferred carbyl and hydrocarbyl groups include straight-chain,branched or cyclic alkyl with 1 to 40, preferably 1 to 25 C-atoms, whichis unsubstituted, mono- or polysubstituted by F, Cl, Br, I or CN, andwherein one or more non-adjacent CH₂ groups are optionally replaced, ineach case independently from one another, by —O—, —S—, —NH—, —NR⁰—,—SiR⁰R⁰⁰—, —CO—, —COO—, —OCO—, —O—CO—O—, —S—CO—, —CO—S—, —SO₂—,—CO—NR⁰—, —NR⁰—CO—, —NR⁰—CO—NR⁰⁰—, —CY¹═CY²— or —C≡C— in such a mannerthat O and/or S atoms are not linked directly to one another, wherein Y¹and Y² are independently of each other H, F, Cl or CN, and R⁰ and R⁰⁰are independently of each other H or an optionally substituted aliphaticor aromatic hydrocarbon with 1 to 20 C atoms.

R⁰ and R⁰⁰ are preferably selected from H, straight-chain or branchedalkyl with 1 to 12 C atoms or aryl with 6 to 12 C atoms.

—CY¹═CY²— is preferably —CH═CH—, —CF═CF— or —CH═C(CN)—.

Halogen is F, Cl, Br or I.

Preferred alkyl groups include, without limitation, methyl, ethyl,n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, 2-methylbutyl,n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl,n-heptyl, cycloheptyl, n-octyl, cyclooctyl, dodecanyl, tetradecyl,hexadecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl,perfluorooctyl, perfluorohexyl etc.

Preferred alkenyl groups include, without limitation, ethenyl, propenyl,butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl,cycloheptenyl, octenyl, cyclooctenyl etc.

Preferred alkynyl groups include, without limitation, ethynyl, propynyl,butynyl, pentynyl, hexynyl, octynyl etc.

Preferred alkoxy groups include, without limitation, methoxy, ethoxy,2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy,t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy etc.

Preferred amino groups include, without limitation, dimethylamino,methylamino, methylphenylamino, phenylamino, etc.

Aryl groups may be mononuclear, i.e. having only one aromatic ring (likefor example phenyl or phenylene), or polynuclear, i.e. having two ormore aromatic rings which may be fused (like for example napthyl ornaphthylene), individually covalently linked (like for examplebiphenyl), and/or a combination of both fused and individually linkedaromatic rings. Preferably the aryl group is an aromatic group which issubstantially conjugated over substantially the whole group.

Aryl and heteroaryl preferably denote a mono-, bi- or tricyclic aromaticor heteroaromatic group with up to 25 C atoms that may also comprisecondensed rings and is optionally substituted.

Preferred aryl groups include, without limitation, benzene, biphenylene,triphenylene, [1,1′:3′,1″]terphenyl-2′-ylene, naphthalene, anthracene,binaphthylene, phenanthrene, pyrene, dihydropyrene, chrysene, perylene,tetracene, pentacene, benzpyrene, fluorene, indene, indenofluorene,spirobifluorene, etc.

Preferred heteroaryl groups include, without limitation, 5-memberedrings like pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole,tetrazole, furan, thiophene, selenophene, oxazole, isoxazole,1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole,1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole,1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-memberedrings like pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine,1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine,1,2,3,5-tetrazine, and fused systems like carbazole, indole, isoindole,indolizine, indazole, benzimidazole, benzotriazole, purine,naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazinimidazole,quinoxalinimidazole, benzoxazole, naphthoxazole, anthroxazole,phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran,dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline,benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine,phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine,quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline,phenanthridine, phenanthroline, thieno[2,3b]thiophene,thieno[3,2b]thiophene, dithienothiophene, dithienopyridine,isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, orcombinations thereof. The heteroaryl groups may be substituted withalkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl or further aryl orheteroaryl substituents.

Preferred arylalkyl groups include, without limitation, 2-tolyl,3-tolyl, 4-tolyl, 2,6-dimethylphenyl, 2,6-diethylphenyl,2,6-di-i-propylphenyl, 2,6-di-t-butylphenyl, o-t-butylphenyl,m-t-butylphenyl, p-t-butylphenyl, 4-phenoxyphenyl, 4-fluorophenyl,3-carbomethoxyphenyl, 4-carbomethoxyphenyl etc.

Preferred alkylaryl groups include, without limitation, benzyl,ethylphenyl, 2-phenoxyethyl, propylphenyl, diphenylmethyl,triphenylmethyl or naphthalinylmethyl.

Preferred aryloxy groups include, without limitation, phenoxy,naphthoxy, 4-phenylphenoxy, 4-methylphenoxy, biphenyloxy,anthracenyloxy, phenanthrenyloxy etc.

The aryl, heteroaryl, carbyl and hydrocarbyl groups optionally compriseone or more subtituents, preferably selected from silyl, sulpho,sulphonyl, formyl, amino, imino, nitrilo, mercapto, cyano, nitro,halogen, C₁₋₁₂alkyl, C₆₋₁₂ aryl, C₁₋₁₂ alkoxy, hydroxy and/orcombinations thereof. The optional substituents may comprise allchemically possible combinations in the same group and/or a plurality(preferably two) of the aforementioned groups (for example amino andsulphonyl if directly attached to each other represent a sulphamoylradical).

Preferred substituents include, without limitation, F, Cl, Br, I, —CN,—NO₂, —NCO, —NCS, —OCN, —SCN, —C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NR⁰R⁰⁰,optionally substituted silyl, aryl with 6 to 40, preferably 6 to 20 Catoms, heteroaryl with 2 to 40, preferably 2 to 20 C atoms, and straightchain or branched alkyl, alkoxy, alkylcarbonyl, alkoxy-carbonyl,alkylcarbonlyoxy or alkoxycarbonyloxy with 1 to 20, preferably 1 to 12 Catoms, wherein one or more H atoms are optionally replaced by F or Cl,wherein R⁰ and R⁰⁰ are as defined above and X⁰ is halogen.

Especially preferred substituents are selected from alkyl, alkoxy,alkenyl, oxaalkyl, thioalkyl, fluoroalkyl and fluoroalkoxy groups asdefined for the preferred groups R^(1,2) below.

If one of R¹⁻⁴ is an alkyl or alkoxy radical, i.e. where the terminalCH₂ group is replaced by —O—, this may be straight-chain or branched. Itis preferably straight-chain, has 2 to 8 carbon atoms and accordingly ispreferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethoxy,propoxy, butoxy, pentoxy, hexyloxy, heptoxy, or octoxy, furthermoremethyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl,pentadecyl, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy ortetradecoxy, for example. Especially preferred are n-hexyl andn-dodecyl.

If one of R¹⁻⁴ is an alkyl group wherein one or more CH₂ groups arereplaced by —CH═CH—, this may be straight-chain or branched. It ispreferably straight-chain, has 2 to 12 C-atoms and accordingly ispreferably vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl,pent-1-, 2-, 3- or pent-4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl,hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- oroct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-,3-, 4-, 5-, 6-, 7-, 8- or dec-9-enyl, undec-1-, 2-, 3-, 4-, 5-, 6-, 7-,8-, 9- or undec-10-enyl, dodec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, -9, -10or undec-11-enyl. The alkenyl group may comprise C═C-bonds with E- orZ-configuration or a mixture thereof.

If one of R¹⁻⁴ is oxaalkyl, i.e. where one CH₂ group is replaced by —O—,is preferably straight-chain 2-oxapropyl (=methoxymethyl),2-(=ethoxymethyl) or 3-oxabutyl (═2-methoxyethyl), 2-, 3-, or4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl,2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonylor 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl, for example.

If one of R¹⁻⁴ is thioalkyl, i.e where one CH₂ group is replaced by —S—,is preferably straight-chain thiomethyl (—SCH₃), 1-thioethyl (—SCH₂CH₃),1-thiopropyl (═—SCH₂CH₂CH₃), 1-(thiobutyl), 1-(thiopentyl),1-(thiohexyl), 1-(thioheptyl), 1-(thiooctyl), 1-(thiononyl),1-(thiodecyl), 1-(thioundecyl) or 1-(thiododecyl), wherein preferablythe CH₂ group adjacent to the sp² hybridised vinyl carbon atom isreplaced.

If one of R¹⁻⁴ is fluoroalkyl or fluoroalkoxy, it is preferably astraight-chain group (O)C_(i)F_(2i+1), wherein i is an integer from 1 to15, in particular CF₃, C₂F₅, C₃F₇, C₄F₉, C₅F₁₁, C₆F₁₃, C₇F₁₅ or C₈F₁₇,very preferably C₆F₁₃, or the corresponding fluoroalkoxy group.

The polymers may also be substituted with a polymerisable or reactivegroup, which is optionally protected during the process of forming thepolymer. Particular preferred polymers of this type are those of formulaI wherein R¹ denotes P-Sp. These polymers are particularly useful assemiconductors or charge transport materials, as they can be crosslinkedvia the groups P, for example by polymerisation in situ, during or afterprocessing the polymer into a thin film for a semiconductor component,to yield crosslinked polymer films with high charge carrier mobility andhigh thermal, mechanical and chemical stability.

Preferably the polymerisable or reactive group P is selected fromCH₂═CW¹—COO—, CH₂═CW¹—CO—,

CH₂═CW²—(O)_(k1)—, CH₃—CH═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH—CH₂)₂CH—OCO—,(CH₂═CH)₂CH—O—, (CH₂═CH—CH₂)₂N—, (CH₂═CH—CH₂)₂N—CO—, HO—CW²W³—,HS—CW²W³—, HW²N—, HO—CW²W³—NH—, CH₂═CW¹—CO—NH—,CH₂═CH—(COO)_(k1)-Phe-(O)_(k2)—, CH₂═CH—(CO)_(k1)-Phe-(O)_(k2)—,Phe-CH═CH—, HOOC—, OCN—, and W⁴W⁵W⁶Si—, with W¹ being H, F, Cl, CN, CF₃,phenyl or alkyl with 1 to 5 C-atoms, in particular H, Cl or CH₃, W² andW³ being independently of each other H or alkyl with 1 to 5 C-atoms, inparticular H, methyl, ethyl or n-propyl, W⁴, W⁵ and W⁶ beingindependently of each other Cl, oxaalkyl or oxacarbonylalkyl with 1 to 5C-atoms, W⁷ and W⁸ being independently of each other H, Cl or alkyl with1 to 5 C-atoms, Phe being 1,4-phenylene that is optionally substitutedby one or more groups L as defined above, and k₁ and k₂ beingindependently of each other 0 or 1.

Alternatively P is a protected derivative of these groups which isnon-reactive under the conditions described for the process according tothe present invention. Suitable protective groups are known to theordinary expert and described in the literature, for example in Green,“Protective Groups in Organic Synthesis”, John Wiley and Sons, New York(1981), like for example acetals or ketals.

Especially preferred groups P are CH₂═CH—COO—, CH₂═C(CH₃)—COO—, CH₂═CH—,CH₂═CH—O—, (CH₂═CH)₂CH—OCO—, (CH₂═CH)₂CH—O—,

or protected derivatives thereof.

Polymerisation of group P can be carried out according to methods thatare known to the ordinary expert and described in the literature, forexample in D. J. Broer; G. Challa; G. N. Mol, Macromol. Chem, 1991, 192,59.

The term “spacer group” is known in prior art and suitable spacer groupsSp are known to the ordinary expert (see e.g. Pure Appl. Chem. 73(5),888 (2001). The spacer group Sp is preferably of formula Sp′-X′, suchthat P-Sp- is P-Sp′-X′—, wherein

-   -   Sp′ is alkylene with up to 30 C atoms which is unsubstituted or        mono- or polysubstituted by F, Cl, Br, I or CN, it being also        possible for one or more non-adjacent CH₂ groups to be replaced,        in each case independently from one another, by —O—, —S—, —NH—,        —NR⁰—, —SiR⁰R⁰⁰—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S—,        —CH═CH— or —C≡C— in such a manner that O and/or S atoms are not        linked directly to one another,    -   X′ is —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR⁰—, —NR⁰—CO—,        —NR⁰—CO—NR⁰⁰—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂—, —CF₂O—, —OCF₂—,        —CF₂S—, —SCF₂—, —CF₂CH₂—, —CH₂CF₂—, —CF₂CF₂—, —CH═N—, —N═CH—,        —N═N—, —CH═CR⁰—, —CY¹═CY²—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH— or a        single bond,    -   R⁰ and R⁰⁰ are independently of each other H or alkyl with 1 to        12 C-atoms, and    -   Y¹ and Y² are independently of each other H, F, Cl or CN.    -   X′ is preferably —O—, —S—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—,        —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —CH₂CH₂—, —CF₂CH₂—, —CH₂CF₂—,        —CF₂CF₂—, —CH═N—, —N═CH—, —N═N—, —CH═CR⁰—, —CY¹=CY²—, —C≡C— or a        single bond, in particular —O—, —S—, —C≡C—, —CY¹═CY²— or a        single bond. In another preferred embodiment X′ is a group that        is able to form a conjugated system, such as —C≡C— or —CY¹═CY²—,        or a single bond.

Typical groups Sp′ are, for example, —(CH₂)_(p)—,—(CH₂CH₂O)_(q)—CH₂CH₂—, —CH₂CH₂—S—CH₂CH₂— or —CH₂CH₂—NH—CH₂CH₂— or—(SiR⁰R⁰—O)_(p)—, with p being an integer from 2 to 12, q being aninteger from 1 to 3 and R⁰ and R⁰⁰ having the meanings given above.

Preferred groups Sp′ are ethylene, propylene, butylene, pentylene,hexylene, heptylene, octylene, nonylene, decylene, undecylene,dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene,ethylene-thioethylene, ethylene-N-methyl-iminoethylene,1-methylalkylene, ethenylene, propenylene and butenylene for example.

The polymers of the present invention can be synthesized according to orin analogy to methods that are known to the skilled person and aredescribed in the literature. Other methods of preparation can be takenfrom the examples. For example, they can be suitably prepared byaryl-aryl coupling reactions, such as Yamamoto coupling, Suzukicoupling, Stille coupling, Sonogashira coupling or Heck coupling. Suzukicoupling and Yamamoto coupling are especially preferred.

The monomers which are polymerised to form the repeat units of thepolymers can be prepared according to methods which are known to theperson skilled in the art.

Another aspect of the invention is a process for preparing a polymer bycoupling one or more identical or different monomers based on a unit offormula I with each other in a polymerisation reaction.

Another aspect of the invention is a process for preparing a polymer bycoupling one or more identical or different monomers based on a unit offormula I, preferably selected of formula II or II1, with each otherand/or with one or more comonomers, in a polymerisation reaction,preferably an aryl-aryl coupling reaction.

Suitable and preferred comonomers are those of the following formulaeR⁷—Ar¹—R⁸R⁷—Ar²—R⁸

wherein Ar¹, Ar², R⁷ and R⁸ are as defined above.

Preferred methods for polymerisation are those leading to C—C-couplingor C—N-coupling, like Suzuki polymerisation, as described for example inWO 00/53656, Yamamoto polymerisation, as described in for example in T.Yamamoto et al., Progress in Polymer Science 1993, 17, 1153-1205 or inWO 2004/022626 A1, and Stille coupling. For example, when synthesizing alinear polymer by Yamamoto polymerisation, monomers as described abovehaving two reactive halide groups R^(7,8) is preferably used. Whensynthesizing a linear polymer by Suzuki polymerisation, preferably amonomer as described above is used wherein at least one reactive groupR^(7,8) is a boronic acid or boronic acid derivative group.

Suzuki polymerisation may be used to prepare homopolymers as well asstatistical, alternating and block random copolymers. Statistical orblock copolymers can be prepared for example from the above monomers offormula II wherein one of the reactive groups R⁷ and R⁸ is halogen andthe other reactive group is a boronic acid or boronic acid derivativegroup. The synthesis of statistical, alternating and block copolymers isdescribed in detail for example in WO 03/048225 A2 or WO 2005/014688 A2.

As alternatives to halogens as described above, preferred leaving groupsare those of formula —O—SO₂Z can be used as R⁷ or R⁸, wherein Z isoptionally substituted alkyl or aryl or a combination thereof,preferably fluorinated alkyl with 1 to 12 C atoms, or aryl or alkylarylwith 6 to 12 C atoms. Particularly preferred examples of such leavinggroups are O-tosylate, O-mesylate, O-triflate and O-nonaflate.

Suzuki polymerisation employs a Pd(0) complex or a Pd(II) salt.Preferred Pd(0) complexes are those bearing at least one phosphineligand such as Pd(Ph₃P)₄. Another preferred phosphine ligand istris(ortho-tolyl)phosphine, i.e. Pd(o-Tol)₄. Preferred Pd(II) saltsinclude palladium acetate, i.e. Pd(OAc)₂. Suzuki polymerisation isperformed in the presence of a base, for example sodium carbonate,potassium phosphate or an organic base such as tetraethylammoniumcarbonate. Yamamoto polymerisation employs a Ni(0) complex, for examplebis(1,5-cyclooctadienyl) nickel(0).

Especially suitable and preferred synthesis methods of the monomer unitsand monomers of formula I and la and their homo- and co-polymers offormula II and IIa are illustrated in the synthesis schemes shownhereinafter. Therein R has one of the meanings of R¹ given in formula I.

Preferred routes tobenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene) 7 areexemplarily illustrated in Scheme 1-3.

Preferred routes tobenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene) 7 areexemplarily illustrated in Schemes 1-2.

3-Bromo-2-thienylzinc bromide is coupled with1,4-dibromo-2,5-diiodobenzene via a palladium-catalysed Negishi couplingto yield tetrabromide 1. Tetrabromide 1 is treated with lithiumdiisopropylamide at cryogenic temperatures followed bychlorotrimethylsilane to yield TMS-protected tetrabromide 2. Treatmentof 2 with n-butyllithium at cryogenic temperatures followed by adialkyldichlorosilane yields TMS-protected benzobis(silolothiophene) 3.Treatment of 3 with N-bromosuccinimide yields benzobis(silolothiophene)dibromide 4.

Following an analogous method to that reported by Shimizu et al. (Angew.Chem. Int. Ed., 2008, 47, 9760), benzobis(silolothiophene) 9 can beprepared as follows: 3-Bromothiophene is treated with n-butyllithium atcryogenic temperatures followed by a dialkyldichlorosilane to yieldchlorosilane 5. Reaction of 5 with 2,5-dibromohydroquinone in thepresence of imidazole yield silyl ether 6. Treatment of 6 witht-butyllithium at cryogenic temperatures followed by aqueous ammoniumchloride at room temperature yields silyl phenol 7. Silyl phenol 7 istreated with triflic anhydride in the presence of a base to yieldditriflate 8. Reaction of 8 with palladium(II) acetate,tricyclohexylphosphine and diethylamine leads to an intramolecularcoupling and yields benzobis(silolothiophene) 9. Treatment of 9 withN-bromosuccinimide yields benzobis(silolothiophene) dibromide 4.

The functionalisation ofbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene) isexemplarily illustrated in Scheme 3.

The homopolymerisation ofbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene) isexemplarily illustrated in Scheme 4.

The co-polymerisation ofbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene) isexemplarily illustrated in Scheme 5.

The novel methods of preparing polymers as described above and below areanother aspect of the invention.

The polymers according to the present invention are useful as chargetransport, semiconducting, electrically conducting, photoconducting orlight mitting materials in optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices.

Especially preferred devices are OFETs, TFTs, ICs, logic circuits,capacitors, RFID tags, OLEDs, OLETs, OPVs, solar cells, laser diodes,photoconductors, photodetectors, electrophotographic devices,electrophotographic recording devices, organic memory devices, sensordevices, charge injection layers, Schottky diodes, planarising layers,antistatic films, conducting substrates and conducting patterns. Inthese devices, the polymers of the present invention are typicallyapplied as thin layers or films.

OFETs where an organic semiconducting (OSC) material is arranged as athin film between a gate dielectric and a drain and a source electrode,are generally known, and are described for example in U.S. Pat. No.5,892,244, WO 00/79617, U.S. Pat. No. 5,998,804, and in the referencescited in the background section. Due to the advantages, like low costproduction using the solubility properties of the polymers according tothe invention and thus the processibility of large surfaces, preferredapplications of these FETs are such as integrated circuitry, TFTdisplays and security applications.

The polymers according to the present invention can also be used inpolymer blends, for example together with other polymers havingcharge-transport, semiconducting, electrically conducting,photoconducting and/or light emitting semiconducting properties, or forexample with polymers having hole blocking or electron blockingproperties for use as interlayers or charge blocking layers in OLEDdevices. Thus, another aspect of the invention relates to a polymerblend comprising one or more polymers according to the present inventionand one or more further polymers having one or more of theabove-mentioned properties. These blends can be prepared by conventionalmethods that are described in prior art and known to the skilled person.Typically the polymers are mixed with each other or dissolved insuitable solvents and the solutions combined.

Another aspect of the invention relates to a formulation comprising oneor more polymers or polmyer blends as described above and below and oneor more organic solvents.

Examples of suitable and preferred organic solvents include, withoutlimitation, dichloromethane, trichloromethane, monochlorobenzene,o-dichlorobenzene, tetrahydrofuran, anisole, morpholine, toluene,o-xylene, m-xylene, p-xylene, 1,4-dioxane, acetone, methylethylketone,1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane,ethyl acetate, n-butyl acetate, dimethylformamide, dimethylacetamide,dimethylsulfoxide, tetraline, decaline, indane, methyl benzoate, ethylbenzoate, mesitylene and/or mixtures thereof.

The concentration of the polymers in the solution is preferably 0.1 to10% by weight, more preferably 0.5 to 5% by weight. Optionally, thesolution also comprises one or more binders to adjust the rheologicalproperties, as described for example in WO 2005/055248 A1.

After the appropriate mixing and ageing, solutions are evaluated as oneof the following categories: complete solution, borderline solution orinsoluble. The contour line is drawn to outline the solubilityparameter-hydrogen bonding limits dividing solubility and insolubility.‘Complete’ solvents falling within the solubility area can be chosenfrom literature values such as published in “Crowley, J. D., Teague, G.S. Jr and Lowe, J. W. Jr., Journal of Paint Technology, 38, No 496, 296(1966)”. Solvent blends may also be used and can be identified asdescribed in “Solvents, W. H. Ellis, Federation of Societies forCoatings Technology, p9-10, 1986”. Such a procedure may lead to a blendof ‘non’ solvents that will dissolve both the polymers of the presentinvention, although it is desirable to have at least one true solvent ina blend.

The polymers according to the present invention can also be used inpatterned OSC layers in the devices as described above and below. Forapplications in modern microelectronics it is generally desirable togenerate small structures or patterns to reduce cost (more devices/unitarea), and power consumption. Patterning of thin layers comprising apolymer according to the present invention can be carried out forexample by photolithography, electron beam lithography or laserpatterning.

For use as thin layers in electronic or electrooptical devices thepolymers, polymer blends or formulations of the present invention may bedeposited by any suitable method. Liquid coating of devices is moredesirable than vacuum deposition techniques. Solution deposition methodsare especially preferred. The formulations of the present inventionenable the use of a number of liquid coating techniques. Preferreddeposition techniques include, without limitation, dip coating, spincoating, ink jet printing, letter-press printing, screen printing,doctor blade coating, roller printing, reverse-roller printing, offsetlithography printing, flexographic printing, web printing, spraycoating, brush coating or pad printing. Ink-jet printing is particularlypreferred as it allows high resolution layers and devices to beprepared.

Selected formulations of the present invention may be applied toprefabricated device substrates by ink jet printing or microdispensing.Preferably industrial piezoelectric print heads such as but not limitedto those supplied by Aprion, Hitachi-Koki, InkJet Technology, On TargetTechnology, Picojet, Spectra, Trident, Xaar may be used to apply theorganic semiconductor layer to a substrate. Additionally semi-industrialheads such as those manufactured by Brother, Epson, Konica, SeikoInstruments Toshiba TEC or single nozzle microdispensers such as thoseproduced by Microdrop and Microfab may be used.

In order to be applied by ink jet printing or microdispensing, thepolymers should be first dissolved in a suitable solvent. Solvents mustfulfil the requirements stated above and must not have any detrimentaleffect on the chosen print head. Additionally, solvents should haveboiling points >100° C., preferably >140° C. and more preferably >150°C. in order to prevent operability problems caused by the solutiondrying out inside the print head. Apart from the solvents method above,suitable solvents include substituted and non-substituted xylenederivatives, di-C₁₋₂-alkyl formamide, substituted and non-substitutedanisoles and other phenol-ether derivatives, substituted heterocyclessuch as substituted pyridines, pyrazines, pyrimidines, pyrrolidinones,substituted and non-substituted N,N-di-C₁₋₂-alkylanilines and otherfluorinated or chlorinated aromatics.

A preferred solvent for depositing a polymer according to the presentinvention by ink jet printing comprises a benzene derivative which has abenzene ring substituted by one or more substituents wherein the totalnumber of carbon atoms among the one or more substituents is at leastthree. For example, the benzene derivative may be substituted with apropyl group or three methyl groups, in either case there being at leastthree carbon atoms in total. Such a solvent enables an ink jet fluid tobe formed comprising the solvent with the polymer, which reduces orprevents clogging of the jets and separation of the components duringspraying. The solvent(s) may include those selected from the followinglist of examples: dodecylbenzene, 1-methyl-4-tert-butylbenzene,terpineol limonene, isodurene, terpinolene, cymene, diethylbenzene. Thesolvent may be a solvent mixture, that is a combination of two or moresolvents, each solvent preferably having a boiling point >100° C., morepreferably >140° C. Such solvent(s) also enhance film formation in thelayer deposited and reduce defects in the layer.

The ink jet fluid (that is mixture of solvent, binder and semiconductingcompound) preferably has a viscosity at 20° C. of 1-100 mPa·s, morepreferably 1-50 mPa·s and most preferably 1-30 mPa·s.

The polymers or formulations according to the present invention canadditionally comprise one or more further components like for examplesurface-active compounds, lubricating agents, wetting agents, dispersingagents, hydrophobing agents, adhesive agents, flow improvers, defoamingagents, deaerators, diluents which may be reactive or non-reactive,auxiliaries, colourants, dyes or pigments, sensitizers, stabilizers,nanoparticles or inhibitors.

An OFET device according to the present invention preferably comprises:

-   -   a source electrode,    -   a drain electrode,    -   a gate electrode,    -   an organic semiconducting (OSC) layer,    -   one or more gate insulator layers,    -   optionally a substrate,

wherein the OSC layer comprises one or more polymers according to thepresent invention.

The gate, source and drain electrodes and the insulating andsemiconducting layer in the OFET device may be arranged in any sequence,provided that the source and drain electrode are separated from the gateelectrode by the insulating layer, the gate electrode and thesemiconductor layer both contact the insulating layer, and the sourceelectrode and the drain electrode both contact the semiconducting layer.The OFET device can be a top gate device or a bottom gate device.Suitable structures and manufacturing methods of an OFET device areknown to the skilled in the art and are described in the literature, forexample in WO 03/052841.

An OPV device according to the present invention preferably comprises:

-   -   a low work function electrode (for example Aluminum),    -   a high work function electrode (for example ITO), one of which        is transparent,    -   a bilayer consisting of a hole transporting and an electron        transporting material; the bilayer can exist as two distinct        layers, or as a blended mixture, a so-called bulk heterjunction        (BHJ) (see for example Coakley, K. M. and McGehee, M. D. Chem.        Mater. 2004, 16, 4533),    -   an optional conducting polymer layer (such as for example        PEDOT:PSS) to modify the work function of the high work function        electrode to provide an ohmic contact for the hole,    -   an optional coating on the high workfunction electrode (such as        LiF) to provide an ohmic contact for electrons.

The hole transporting polymer in the blend exists of one of the polymersof the present invention. The electron transporting material can be aninorganic material such as zinc oxide or cadmium selenide, or an organicmaterial such as a fullerene derivate (for example PCBM, [(6,6)-phenylC61-butyric acid methyl ester] or a polymer see for example Coakley, K.M. and McGehee, M. D. Chem. Mater. 2004, 16, 4533). For the blendedmixture, an optional annealing step may be necessary to optimize blendmorpohology and consequently OPV device performance.

In security applications, OFETs and other devices with semiconductingmaterials according to the present invention, like transistors ordiodes, can be used for RFID tags or security markings to authenticateand prevent counterfeiting of documents of value like banknotes, creditcards or ID cards, national ID documents, licenses or any product withmonetry value, like stamps, tickets, shares, cheques etc.

Alternatively, the materials according to the invention can be used inorganic light emitting devices or diodes (OLEDs), e.g., in displayapplications or as backlight of e.g. liquid crystal displays. CommonOLEDs are realized using multilayer structures. An emission layer isgenerally sandwiched between one or more electron-transport and/orhole-transport layers. By applying an electric voltage electrons andholes as charge carriers move towards the emission layer where theirrecombination leads to the excitation and hence luminescence of thelumophor units contained in the emission layer. The inventive compounds,materials and films may be employed in one or more of the chargetransport layers and/or in the emission layer, corresponding to theirelectrical and/or optical properties. Furthermore their use within theemission layer is especially advantageous, if the compounds, materialsand films according to the invention show electroluminescent propertiesthemselves or comprise electroluminescent groups or compounds. Theselection, characterization as well as the processing of suitablemonomeric, oligomeric and polymeric compounds or materials for the usein OLEDs is generally known by a person skilled in the art, see, e.g.,Meerholz, Synthetic Materials, 111-112, 2000, 31-34, Alcala, J. Appl.Phys., 88, 2000, 7124-7128 and the literature cited therein.

According to another use, the materials according to the presentinvention, especially those which show photoluminescent properties, maybe employed as materials of light sources, e.g., of display devices suchas described in EP 0 889 350 A1 or by C. Weder et al., Science, 279,1998, 835-837.

A further aspect of the invention relates to both the oxidised andreduced form of the polymers according to this invention. Either loss orgain of electrons results in formation of a highly delocalised ionicform, which is of high conductivity. This can occur on exposure tocommon dopants. Suitable dopants and methods of doping are known tothose skilled in the art, e.g. from EP 0 528 662, U.S. Pat. No.5,198,153 or WO 96/21659.

The doping process typically implies treatment of the semiconductormaterial with an oxidating or reducing agent in a redox reaction to formdelocalised ionic centres in the material, with the correspondingcounterions derived from the applied dopants. Suitable doping methodscomprise for example exposure to a doping vapor in the atmosphericpressure or at a reduced pressure, electrochemical doping in a solutioncontaining a dopant, bringing a dopant into contact with thesemiconductor material to be thermally diffused, and ion-implantantionof the dopant into the semiconductor material.

When electrons are used as carriers, suitable dopants are for examplehalogens (e.g., I₂, Cl₂, Br₂, ICl, ICl₃, IBr and IF), Lewis acids (e.g.,PF₅, AsF₅, SbF₅, BF₃, BCl₃, SbCl₅, BBr₃ and SO₃), protonic acids,organic acids, or amino acids (e.g., HF, HCl, HNO₃, H₂SO₄, HClO₄, FSO₃Hand ClSO₃H), transition metal compounds (e.g., FeCl₃, FeOCl, Fe(ClO₄)₃,Fe(4-CH₃C₆H₄SO₃)₃, TiCl₄, ZrCl₄, HfCl₄, NbF₅, NbCl₅, TaCl₅, MoF₅, MoCl₅,WF₅, WCl₆, UF₆ and LnCl₃ (wherein Ln is a lanthanoid), anions (e.g.,Cl⁻, Br⁻, I⁻, I₃ ⁻, HSO₄ ⁻, SO₄ ²⁻, NO₃ ⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻,SbF₆ ⁻, FeCl₄ ⁻, Fe(CN)₆ ³⁻, and anions of various sulfonic acids, suchas aryl-SO₃ ⁻). When holes are used as carriers, examples of dopants arecations (e.g., H⁺, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺), alkali metals (e.g., Li,Na, K, Rb, and Cs), alkaline-earth metals (e.g., Ca, Sr, and Ba), O₂,XeOF₄, (NO₂ ⁺)(SbF₆ ⁻), (NO₂ ⁺)(SbCl₆ ⁻), (NO₂ ⁺)(BF₄ ⁻), AgClO₄,H₂IrCl₆, La(NO₃)₃. 6H₂O, FSO₂OOSO₂F, Eu, acetylcholine, R₄N⁺, (R is analkyl group), R₄P⁺ (R is an alkyl group), R₆As⁺ (R is an alkyl group),and R₃S⁺ (R is an alkyl group).

The conducting form of the polymers of the present invention can be usedas an organic “metal” in applications including, but not limited to,charge injection layers and ITO planarising layers in OLED applications,films for flat panel displays and touch screens, antistatic films,printed conductive substrates, patterns or tracts in electronicapplications such as printed circuit boards and condensers.

According to another use, the materials according to the presentinvention can be used alone or together with other materials in or asalignment layers in LCD or OLED devices, as described for example in US2003/0021913. The use of charge transport compounds according to thepresent invention can increase the electrical conductivity of thealignment layer. When used in an LCD, this increased electricalconductivity can reduce adverse residual dc effects in the switchableLCD cell and suppress image sticking or, for example in ferroelectricLCDs, reduce the residual charge produced by the switching of thespontaneous polarisation charge of the ferroelectric LCs. When used inan OLED device comprising a light emitting material provided onto thealignment layer, this increased electrical conductivity can enhance theelectroluminescence of the light emitting material. The compounds ormaterials according to the present invention having mesogenic or liquidcrystalline properties can form oriented anisotropic films as describedabove, which are especially useful as alignment layers to induce orenhance alignment in a liquid crystal medium provided onto saidanisotropic film. The materials according to the present invention mayalso be combined with photoisomerisable compounds and/or chromophoresfor use in or as photoalignment layers, as described in US 2003/0021913.

According to another use the materials according to the presentinvention, especially their water-soluble derivatives (for example withpolar or ionic side groups) or ionically doped forms, can be employed aschemical sensors or materials for detecting and discriminating DNAsequences. Such uses are described for example in L. Chen, D. W.McBranch, H. Wang, R. Helgeson, F. Wudl and D. G. Whitten, Proc. Natl.Acad. Sci. U.S.A. 1999, 96, 12287; D. Wang, X. Gong, P. S. Heeger, F.Rininsland, G. C. Bazan and A. J. Heeger, Proc. Natl. Acad. Sci. U.S.A.2002, 99, 49; N. DiCesare, M. R. Pinot, K. S. Schanze and J. R.Lakowicz, Langmuir 2002, 18, 7785; D. T. McQuade, A. E. Pullen, T. M.Swager, Chem. Rev. 2000, 100, 2537.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

Throughout the description and claims of this specification, the words“comprise” and “contain” and variations of the words, for example“comprising” and “comprises”, mean “including but not limited to”, andare not intended to (and do not) exclude other components.

It will be appreciated that variations to the foregoing embodiments ofthe invention can be made while still falling within the scope of theinvention. Each feature disclosed in this specification, unless statedotherwise, may be replaced by alternative features serving the same,equivalent or similar purpose. Thus, unless stated otherwise, eachfeature disclosed is one example only of a generic series of equivalentor similar features.

All of the features disclosed in this specification may be combined inany combination, except combinations where at least some of suchfeatures and/or steps are mutually exclusive. In particular, thepreferred features of the invention are applicable to all aspects of theinvention and may be used in any combination. Likewise, featuresdescribed in non-essential combinations may be used separately (not incombination).

The invention will now be described in more detail by reference to thefollowing examples, which are illustrative only and do not limit thescope of the invention.

EXAMPLE 1 Preparation of2,2′-(2,5-dibromobenzene-1,4-diyl)bis(3-bromothiophene)

A oven dried 2000 cm³ flask is charged with1,4-dibromo-2,5-diiodobenzene (61.00 g, 125.1 mmol),dichlorobis(triphenylphosphine)palladium(II) (2.195 g, 3.127 mmol) andanhydrous tetrahydrofuran (300 cm³). Once the starting materials aredissolved, a solution of 0.5 M of 3-bromo-2-thienylzinc bromide intetrahydrofuran (500 cm³, 250.2 mmol) is transfered using a canula andthe reaction heated to 85° C. for 3 hours. The reaction is cooled downovernight and the white precipitate filtered off. This precipitate iswashed with water (750 cm³) and methanol (250 cm³) to obtain 25.77 g ofthe title product. Further product is recovered from the initialfiltrate. The filtrate is reduced to ca. 90 cm³ in vacuo and then 500cm³ of methanol is added. The precipitate is filtered off, washed withwater (750 cm³) and methanol (250 cm³) and finally triturated threetimes in hot propan-2-ol to obtain an additional 12.72 g of the titleproduct. (38.49 g, Yield: 55%). NMR (¹H, 300 MHz, CDCl₃): δ 7.71 (s,2H); 7.42 (d, J=5.3 Hz, 2H); 7.09 (d, J=5.3 Hz, 2H). NMR (¹³C, 75 MHz,CDCl₃): δ 136.62; 136.10; 135.16; 130.50; 126.97; 123.52; 111.78.

Preparation of2,2′-(2,5-dibromobenzene-1,4-diyl)bis(3-bromo-5-trimethylsilyl-thiophene)

A oven dried 1000 cm³ three neck flask is charged with2,2′-(2,5-dibromobenzene-1,4-diyl)bis(3-bromothiophene) (12.00 g, 21.51mmol) and anhydrous THF (430 cm³). The reaction is cooled down to −78°C. using a acetone dry ice bath, and then a 2.0M solution (22.0 cm³,44.1 mmol) of lithium diisopropylamide intetrahydrofuran/heptane/ethylbenzene is added dropwise. After theaddition completion, the reaction mixture is kept at 78° C. for a hour,and then chlorotrimethylsilane (6.00 cm³, 47.3 mmol) is added quickly.The reaction is allowed to reach 23° C. overnight, and then methanol(100 cm³) and water (400 cm³) is added. The mixture is extracted withdiethyl ether (3×300 cm³). The combined organic phases are washed withdiluted aqueous chlorhydric acid (3×250 cm³) and water (300 cm³), driedover magnesium sulfate, and then the solvent removed in vacuo. The crudeproduct is recrystallized in propan-2-ol to obtain the title product.(11.12 g, Yield: 74%). NMR (¹H, 300 MHz, CDCl₃): δ 7.68 (s, 2H); 7.16(s, 2H); 0.36 (s, 18H). NMR (¹³C, 75 MHz, CDCl₃): δ 142.52; 139.96;136.60; 136.39; 136.25; 123.11; 112.71, −0.16.

Preparation of2,7-dibromo-5,5,10,10-tetraoctylbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene

A oven dried 50 cm³ flask is charged with5,5,10,10-tetraoctylbenzo-2,7-bistrimethylsilyl-benzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene(0.900 g, 1.01 mmol) and anhydrous tetrahydrofuran (30 cm³). Once thesolid is dissolved, N-bromosuccinimide (0.360 g, 2.02 mmol) is added inthe three portions. The reaction is monitored by HPLC and small portions(10 mg) of N-bromosuccinimide are added until reaction completion. Thereaction is quenched with water (75 cm³) and extracted with diethylether (3×50 cm³). The combined organic fractions are dried overmagnesium sulfate, filtered and evaporated in vacuo. The crude productis purified by column chromatography over silica with petroleum ether aseluent, and then three times over reverse phase silica (C18) with firsttetrahydrofuran/acetonitrile (50:50, volume) thantetrahydrofuran/acetonitrile (40:60, volume) and finallytetrahydrofuran/acetonitrile (50:50, volume) as eluent. (295 mg, Yield:32%). NMR (¹H, 300 MHz, CDCl₃): δ 7.42 (s, 2H); 7.05 (s, 2H); 1.36 (m,8H); 1.22 (m, 40H); 0.93 (m, 8H); 0.86 (t, J=6.8 Hz, 12H). NMR (¹³C, 75MHz, CDCl₃): δ 157.28; 142.20; 141.11; 140.03; 132.52; 125.03; 112.26;33.38; 32.01; 29.37; 29.25; 24.14; 22.81; 14.26; 12.09.

Preparation of5,5,10,10-tetraoctyl-2,7-bistrimethylsilyl-benzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene

A oven dried 1000 cm³ three neck flask is charged with2,2′-(2,5-dibromobenzene-1,4-diyl)bis(3-bromo-5-trimethylsilylthiophene)(6.500 g, 9.255 mmol) and anhydrous tetrahydrofuran (325 cm³). Thereaction is cooled down to −78° C. using a acetone dry ice bath and a2.5 M solution of n-butyllithium in hexanes (16.7 cm³, 41.6 mmol) isadded dropwise over 30 mins. The lithium-halogenure exchange reaction ismonitored by GC-MS. A additional quantity of a 2.5 M solution ofn-butyllithium in hexanes (0.57 cm³, 1.43 mmol) is added to fullycomplete the lithium-halogenure exchange reaction, and then thedi-n-octyldichlorosilane (6.6 cm³, 19.0 mmol) is added slowly. Thecooling bath is removed and the reaction mixture is allowed to reach 23°C. After 1 hour at 23° C., the reaction is quenched with water (100 cm³)and extracted with diethyl ether (3×250 cm³). The combined organicfractions are dried over magnesium sulfate, filtered and evaporated invacuo. The crude product is purified by column chromatography withpetroleum ether as eluent. (1.024 g, Yield: 9.8%, purity (HPLC): 79%).NMR (¹H, 300 MHz, CDCl₃): δ 7.57 (s, 2H); 7.20 (s, 2H); 1.39 (m, 8H);1.22 (m, 40H); 0.92 (m, 8H); 0.85 (t, J=6.9 Hz, 12H) 0.35 (s, 18H). NMR(¹³C, 75 MHz, CDCl₃): δ 162.70; 142.56; 142.28; 141.63; 140.97; 136.81;125.60; 33.45; 32.04; 29.42; 24.25; 22.83; 14.27; 12.26; 1.48; 0.28.

EXAMPLE 2 Preparation of5,5,10,10-tetra-2′-ethylhexyl-2,7-bistrimethylsilyl-benzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene

A oven dried 1000 cm³ three neck flask is charged with2,2′-(2,5-dibromobenzene-1,4-diyl)bis(3-bromo-5-trimethylsilylthiophene)(11.00 g, 15.66 mmol) and anhydrous tetrahydrofuran (550 cm³). Thereaction is cooled down to −78° C. using a acetone dry ice bath and a2.5 M solution of n-butyllithium in hexanes (28.2 cm³, 70.5 mmol) isadded dropwise over 30 mins. The lithium-halogenure exchange reaction ismonitored by GC-MS. A additional quantity of a 2.5 M solution ofn-butyllithium in hexanes (1.55 cm³, 3.88 mmol) is added to fullycomplete the lithium-halogenure exchange reaction, and thendi-2-ethylhexyldichlorosilane (10.45 g, 32.11 mmol) is added slowly. Thecooling bath is removed and the reaction mixture is allowed to reach 23°C. After 1 hour at 23° C., the reaction is quenched with water (200 cm³)and extracted with diethyl ether (3×250 cm³). The combined organicfractions are dried over magnesium sulfate, filtered and evaporated invacuo. The crude product is purified by column chromatography withpetroleum ether as eluent. (1.020 g, Yield: 6.8%, purity (HPLC): 93%).NMR (¹H, 300 MHz, CDCl₃): δ 7.57 (s, 2H); 7.19 (s, 2H); 1.39 (m, 4H);1.22 (m, 12H); 1.12 (m, 24H); 0.95 (m, 4H); 0.75 (m, 24H); 0.33 (s,18H). NMR (¹³C, 75 MHz, CDCl₃): δ 162.48; 143.21; 142.13; 141.66;141.29; 137.12; 125.56; 36.01; 35.77; 29.10; 28.97; 23.13; 18.09; 14.33;10.94; 0.22.

Preparation of2,7-dibromo-5,5,10,10-tetra-2′-ethylhexyl-benzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene

A oven dried 100 cm³ flask is charged with5,5,10,10-tetra-2′-ethylhexy-benzo-2,7-bistrimethylsilyl-benzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene(0.920 g, 1.03 mmol) and anhydrous tetrahydrofuran (50 cm³). Once thesolid is dissolved, N-bromosuccinimide (0.367 g, 2.06 mmol) is added inthe three portions. The reaction is monitored by HPLC and small portions(10 mg) of N-bromosuccinimide are added until reaction completion. Thereaction is quenched with water (75 cm³) and extracted with diethylether (3×50 cm³). The combined organic fractions are dried overmagnesium sulfate, filtered and evaporated in vacuo. The crude productis purified by column chromatography over silica with petroleum ether aseluent, and then two times over reverse phase silica (C18) with firsttetrahydrofuran/acetonitrile (45:55, volume) and finallytetrahydrofuran/acetonitrile (40:60, volume) as eluent. (399 mg, Yield:43%). NMR (¹H, 300 MHz, CDCl₃): δ 7.43 (s, 2H); 7.04 (s, 2H); 1.39 (m,4H); 1.22 (m, 12H); 1.12 (m, 24H); 0.95 (m, 4H); 0.75 (m, 24H). NMR(¹³C, 75 MHz, CDCl₃): δ 157.10; 141.96; 140.91; 140.79; 132.72; 125.04;112.07; 35.88; 35.61; 29.00; 28.81; 23.09; 17.91; 14.31; 10.91.

EXAMPLE 3 Preparation ofpoly[2,7-(5,5,10,10-tetraoctylbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene))-alt-4,7-(2,1,3-benzothiadiazole)]

In a dried flask,2,7-dibromo-5,5,10,10-tetraoctylbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene(177.0 mg, 0.1955 mmol),4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,1,3-benzothiadiazole(75.9 mg, 0.1955 mmol), tris(dibenzylideneacetone)dipalladium(0) (3.6mg, 0.0039 mmol) and tri(o-tolyl)phosphine (4.8 mg, 0.0156 mmol) weredissolved in degassed toluene (5.0 cm³) and degassed 2 M aqueous sodiumcarbonate (0.5 cm³). The reaction mixture was vigorously stirred at100-105° C. for 24 hours. The polymer was purified by precipitation intomethanol:water (10:1), filtered and washed sequentially via Soxhletextraction with acetone, petroleum ether and chloroform. The chloroformfractions were reduced to a smaller volume under reduced pressure andprecipitated into methanol. The precipitated polymer was filtered anddried under vacuum at 25° C. overnight to afford the title product(acetone fraction: 110 mg, yield 64%; CHCl₃ fraction: 10 mg, yield 6%).GPC (PhCl, 60° C., CHCl₃ fraction) M_(w)=8,600 g/mol, M_(n)=4,600 g/mol;λ_(max) (PhCl)=510 nm.

EXAMPLE 4Poly[2,7-(5,5,10,10-tetra-2′-ethylhexylbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene))-alt-4,7-(2,1,3-benzothiadiazole)]

In a dried flask,2,7-dibromo-5,5,10,10-tetra-2′-ethylhexylbenzo[1″,2″:4,5;4″,5″:4′,5′]-bis(silolo[3,2-b:3′,2′-b′]thiophene(200.0 mg, 0.2210 mmol),4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,1,3-benzothiadiazole(85.8 mg, 0.2210 mmol), tris(dibenzylideneacetone)dipalladium(0) (4.0mg, 0.0044 mmol) and tri(o-tolyl)phosphine (5.4 mg, 0.0177 mmol) weredissolved in degassed toluene (5.0 cm³) and degassed 2 M aqueous sodiumcarbonate (0.5 cm³). The reaction mixture was vigorously stirred at100-105° C. for 24 hours. The polymer was purified by precipitation intomethanol:water (10:1), filtered and washed sequentially via Soxhletextraction with acetone, petroleum ether and chloroform. The acetone andchloroform fractions were reduced to a smaller volume under reducedpressure and precipitated into methanol. The precipitated polymer wasfiltered and dried under vacuum at 25° C. overnight to afford the titleproduct (acetone fraction: 99 mg, yield 51%; CHCl₃ fraction: 12 mg,yield 6%). GPC (PhCl, 60° C., CHCl₃ fraction) M_(w)=39,800 g/mol,M_(n)=15,700 g/mol; λ_(max) (PhCl)=515 nm.

The invention claimed is:
 1. Conjugated polymer comprising one or moreidentical or different repeating units of formula I

wherein one of A¹ and A² is a single bond and the other is SiR¹R², oneof A³ and A⁴ is a single bond and the other is SiR³R⁴, one of U¹ and U²is —CH═ or ═CH— and the other is —X—, one of U³ and U⁴ is —CH═ or ═CH—and the other is —X—, X is in each occurrence independently selectedfrom —S— and —Se—, R¹⁻⁴ are independently of each other identical ordifferent groups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN,—SCN, —C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, P is apolymerisable group, Sp is a spacer group or a single bond, X⁰ ishalogen, R⁰ and R⁰⁰ are independently of each other H or an optionallysubstituted carbyl or hydrocarbyl group optionally comprising one ormore hetero atoms, Ar¹ and Ar² are independently of each other anoptionally substituted aryl or heteroaryl group, —CY¹═CY²— or —C≡C—, Y¹and Y² are independently of each other H, F, Cl or CN, m1 and m2 areindependently of each other 0 or 1, 2, 3 or
 4. 2. Polymer according toclaim 1, characterized in that it is selected of formula Ia

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1 and m2 have the meanings of claim 1 andn is an integer >1.
 3. The polymer according to claim 2, selected-offormula Ib

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1, m2 and n have the meanings of claim 2,and R⁵ and R⁶ do independently of each other have one of the meanings ofR¹ or denote H, halogen, —CH₂Cl, —CHO, —CH═CH₂—SiR′R″R″′, —SnR′R″R″′,—BR′R″, —B(OR′)(OR″), —B(OH)₂, or P-Sp, wherein P and Sp are as definedabove, and R′, R″ and R′″ have independently of each other one of themeanings of R⁰ given above and R′ and R″ may also form a ring togetherwith the hetero atom to which the are attached.
 4. Monomer of formula II

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1 and m2 have the meanings of claim 1,and R⁷ and R⁸ denote independently of each other halogen, —CH₂Cl, —CHO,—CH═CH₂, —SiR′R″R″, —SnR′R″R″′, —BR′R″, —B(OR′)(oR″)(OR″), —B(OH)₂, aleaving group or P-Sp, wherein P and Sp are as defined above, and R′, R″and R″′ have independently of each other one of the meanings of R⁰ givenabove or denote halogen, and R′ and R″ may also form a ring togetherwith the hetero atom to which they are attached.
 5. Polymer according toclaim 1, wherein R¹⁻⁴ are independently of each other selected fromstraight-chain or branched-chain, C₁-C₂₀-alkyl, C₁-C₂₀-alkoxy,C₂-C₂₀-alkenyl, C₂-C₂₀-alkynyl, C₁-C₂₀-thioalkyl, C₁-C₂₀-silyl,C₁-C₂₀-ester, C₁-C₂₀-amino, C₁-C₂₀-fluoroalkyl.
 6. Polymer according toclaim 1, characterized in that Ar¹ and Ar² are independently of eachother selected from the group consisting of2,1,3-benzothiadiazole-4,7-diyl, 2,1,3-benzoselenadiazole-4,7-diyl,2,3-dicyano-1,4-phenylene, 2,5-dicyano, 1,4-phenylene,2,3-difluoro-1,4-phenylene, 2,5-difluoro, 1,4-phenylene,2,3,5,6-tetrafluoro, 1,4-phenylene, 3,4-difluorothiophene-2,5-diyl,thieno[3,4-b]pyrazine-2,5-diyl, quinoxaline-5,8-diyl,selenophene-2,5-diyl, thiophene-2,5-diyl,thieno[3,2-b]thiophene-2,5-diyl, thieno[2,3-b]thiophene-2,5-diyl,selenopheno[3,2-b]selenophene-2,5-diyl,selenopheno[2,3-b]selenophene-2,5-diyl,selenopheno[3,2-b]thiophene-2,5-diyl,selenopheno[2,3-b]thiophene-2,5-diyl, 1,4-phenylene, pyridine-2,5-diyl,pyrimidine-2,5-diyl, p-p′-biphenyl, naphthalene-2,6-diyl,benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl, 2,2-dithiophene,2,2-diselenophene, thiazole and oxazole, all of which are unsubstituted,mono- or polysubstituted with R¹ as defined in claim
 1. 7. Polymer blendcomprising one or more polymers according to claim 1 and one or moreadditional polymers not of claim
 1. 8. The polymer blend of claim 7wherein the one or more additional polymers are selected from polymershaving semiconducting, charge transport, hole/electron transport,hole/electron blocking, electrically conducting, photoconducting orlight emitting properties.
 9. A formulation comprising one or morepolymers according to claim 1 and one or more solvents and optionally anadditional polymer.
 10. The formulation of claim 9 wherein the solventsare organic solvents.
 11. An optical, electrooptical, electronic,electroluminescent or photoluminescent components or devices comprisinga polymer of claim 1, a polymer blend comprising one or more polymersaccording to claim 1 and one or more polymers, selected from polymershaving semiconducting, charge transport, hole/electron transport,hole/electron blocking, electrically conducting, photoconducting orlight emitting properties, or a formulation comprising one or morepolymers or polymer blends according to claim 1 and one or moresolvents, selected from organic solvents.
 12. Optical, electrooptical orelectronic component or device comprising one or more polymers,according to claim 1 and optionally at least one additional of merand/or a solvent.
 13. Component or device according to claim 12,characterized in that it is selected from the group consisting oforganic field effect transistors (OFET), thin film transistors (TFT),integrated circuits (IC), logic circuits, capacitors, radio frequencyidentification (RFID) tags, devices or components, organic lightemitting diodes (OLED), organic light emitting transistors (OLET), flatpanel displays, backlights of displays, organic photovoltaic devices(OPV), solar cells, laser diodes, photoconductors, photodetectors,electrophotographic devices, electrophotographic recording devices,organic memory devices, sensor devices, charge injection layers, chargetransport layers or interlayers in polymer light emitting diodes(PLEDs), Schottky diodes, planarising layers, antistatic films, polymerelectrolyte membranes (PEM), conducting substrates, conducting patterns,electrode materials in batteries, alignment layers, biosensors,biochips, security markings, security devices, and components or devicesfor detecting and discriminating DNA sequences.
 14. Component or deviceaccording to claim 13, which is a bulk heterojunction OPV device. 15.Process of preparing a polymer according to claim 1, by subjecting oneor more monomers of formula II

wherein U¹⁻⁴, A¹⁻⁴, Ar^(1,2), m1 and m2 have the meanings of claim 1,and R⁷ and R⁸ denote independently of each other halogen, —CH₂Cl, —CHO,—CH═CH₂, —SiR′R″R″′, —SnR′R″R″′, —BR′R″, —B(OR′)(OR″), —B(OH)₂, aleaving group or P-Sp, wherein P and Sp are as defined above, and R′, R″and R′″ have independently of each other one of the meanings of R⁰ givenabove or denote halogen, and R′ and R″ may also form a ring togetherwith the hetero atom to which they are attached, and optionally one ormore monomers of formula R⁷—Ar¹—R⁸ and/or R⁷—Ar²—R⁸ wherein R⁷, R⁸, Ar¹and Ar² are as defined above, to an aryl-aryl coupling reaction. 16.Polymer comprising one or more identical or different repeating unitsselected from the following subformulae:

wherein R¹⁻⁴ are independently of each other identical or differentgroups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, n is aninteger >1, and Ar an optionally substituted aryl or heteroaryl group,—CY¹═CY²— or —C≡C P is a polymerisable group, Sp is a spacer group or asingle bond, X⁰ is halogen, R⁰ and R⁰⁰ are independently of each other Hor an optionally substituted carbyl or hydrocarbyl group optionallycomprising one or more hetero atoms, and Y¹ and Y² are independently ofeach other H, F, Cl or CN.
 17. Polymer according to claim 16, ofsub-formula Ia1-(MU)_(n)-  Ia1 wherein n is an integer >1 and “MU” is a monomericrepeating unit selected from the group consisting of subformulae I1-I32

wherein R¹⁻⁴ is as defined in claim 16 and Ar is as defined in claim 16.18. A polymer formula Ib1:R⁵-(MU)_(n)-R⁶  Ib1 wherein R⁵ and R⁶ are R¹, H, halogen, —CH₂Cl, —CHO,—CH═CH₂—SiR′R″R″′, —SnR′R″R″′, —BR′R″, —B(OR′)(OR″), —B(OH)₂, or P-Sp,R′, R″ and R′″ are independently of each other H or an optionallysubstituted carbyl or hydrocarbyl group optionally comprising one ormore hetero atoms and R′ and R″ may also form a ring together with thehetero atom to which the are attached P is a polymerisable group, Sp isa spacer group or a single bond, X⁰ is halogen, and n is an integer >1,and “MU” is a monomeric repeating unit selected from subformulae I1-I32

wherein R¹⁻⁴ are independently of each other identical or differentgroups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, n is aninteger >1 and Ar is a single bond, SiR¹R², or an optionally substitutedaryl or heteroaryl group, —CY¹═CY²— or —C≡C— P is a polymerisable group,Sp is a spacer group or a single bond, X⁰ is halogen, R⁰ and R⁰⁰ areindependently of each other H or an optionally substituted carbyl orhydrocarbyl group optionally comprising one or more hetero atoms, and Y¹and Y² are independently of each other H, F, Cl or CN.
 19. A monomer offormula II1:R⁷-MU-R⁸  II1 wherein R⁷ and R⁸ are as defined in claim 4, and “MU” is amonomeric unit selected from subformulae I1-I32

wherein R¹⁻⁴ are independently of each other identical or differentgroups selected from H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN,—C(═O)NR⁰R⁰⁰, —C(═O)X⁰, —C(═O)R⁰, —NH₂, —NR⁰R⁰⁰, —SH, —SR⁰, —SO₃H,—SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, P-Sp-, optionally substituted silyl, orcarbyl or hydrocarbyl with 1 to 40 C atoms that is optionallysubstituted and optionally comprises one or more hetero atoms, n is aninteger >1 and Ar is an optionally substituted aryl or heteroaryl group,—CY¹═CY²— or —C≡C— P is a polymerisable group, Sp is a spacer group or asingle bond, X⁰ is halo en R⁰ and R⁰⁰ are independently of each other Hor an optionally substituted carbyl or hydrocarbyl group optionallycomprising one or more hetero atoms, and Y¹ and Y² are independently ofeach other H, F, Cl or CN.